CVE-2026-90035 drm/amd/display: fix division by zero in get_estimated_bw()
A malicious USB4/DPIA device can trigger a division by zero in the Linux kernel, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-90035?
CVE-2026-90035 is a denial of service vulnerability in Linux, published on 16 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: fix division by zero in get_estimated_bw()
get_estimated_bw() divides by link->dpia_bw_alloc_config.bw_granularity, which is zeroed by reset_bw_alloc_struct() and only populated once DP_TUNNELING_BW_ALLOC_CAP_CHANGED has been handled.
link_dp_dpia_handle_bw_alloc_status(), the DPCD interrupt handler, calls get_estimated_bw() whenever DP_TUNNELING_ESTIMATED_BW_CHANGED is set, independently of whether DP_TUNNELING_BW_ALLOC_CAP_CHANGED has ever fired for that link. A connected USB4/DPIA tunneling device that reports an estimated-bandwidth change before ever reporting a capability change drives a division by zero in this IRQ path.
link_dpia_send_bw_alloc_request() already guards the same bw_granularity division; add the identical guard here rather than introducing a new pattern.
(cherry picked from commit f2a961457c33dc34223aad5c9e8971de34a4eed3)
Which versions are affected by CVE-2026-90035?
How do I fix CVE-2026-90035?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-90035 being exploited?
There is no known exploitation of CVE-2026-90035 in the wild and no public exploit code.
Sources
Also known as AZL-101187, BELL-CVE-2026-90035, DEBIAN-CVE-2026-90035, GHSA-535w-j2qq-gp7f, UBUNTU-CVE-2026-90035.